This invention relates to a process for the production of radically post-crosslinked polymers. In the process according to the invention, one or more special acrylic or methacrylic acid derivatives based on naturally occurring oils is/are reacted with aromatic and/or aliphatic isocyanates and the polyurethanes thus obtained are subsequently subjected to radical post-crosslinking in the presence of a radical initiator.
The use of radiation curing in the coating industry for producing high-quality coating materials is known from the prior art. In radiation curing, olefinically unsaturated compounds (monomers, oligomers, polymers, prepolymers), i.e. compounds containing C═C double bonds as structural elements, are cured by exposure to high-energy radiation, for example UV light or electron beams. The actual radiation curing process is sometimes preceded by physical drying.
It is also known that particularly high-quality coatings are obtained in radiation curing when the olefinically unsaturated starting compounds used contain polyurethane groups as further structural elements. Unsaturated radiation-curable urethane acrylates are known from Manfred Bock (Ed. Ulrich Zorill), “Polyurethane für Lacke und Beschichtungen”, Hannover 1999, pages 73-74.
U.S. Pat. No. 3,979,270 describes a process for the curing of amine derivatives of reaction products of acrylated epoxidized soybean oil in which curing is carried out by high-energy radiation.